MS Teams Smartsheet Login Issue



I have added the Smartsheet tab to my teams channel. It was working previously, but now when I click on the tab, there is a message from Smartsheet saying I need to login to my account to access this published item.

I click the 'sign in' button, which opens a new tab in my web browser, but then it immediately closes itself.

I am successfully logged into the Smartsheet website outside of the teams application while this is going on.

Any help would be appreciated.